The present invention relates to a machine for producing iced beverages (water-ices and the like), of the type comprising a tank containing the beverage and in which a cooling element and a stirring element for circulation of the beverage are present. The tank further comprises a dispensing tap from which the beverage to be served is drew off.
Since these machines are intended for food use, obviously the hygienic conditions of the product must be ensured. From this point of view an element causing many problems is the dispensing tap. In fact, in the machines of the known art, the tap that is generally made as a mere cylindrical slidable piston and is operated by an outer lever, has regions into which the beverage penetrates and stagnates and cleaning of which is made difficult. These regions in a short period of time become a breeding-ground for bacteria and give rise to pollution of the product.
The risky regions in a tap were found to be substantially two.
The first region is identified by the interface between the side wall of the piston and the seat in which the piston slides; the liquid penetrating through this gap inevitably stagnates and since it is no longer cooled, it is subjected to quick deterioration. In the known art attempts were made to solve this problem by making the volume of this gap increasingly smaller through reduction of the play between the piston and seat as much as possible, trying to substantially eliminate the amount of stagnating liquid. Unfortunately even very small amounts of stagnating liquid generate bacteria over time.
The second region that appeared to be a source of pollution is represented by a region beyond the sealing elements surrounding the sliding piston, towards the fitting end of the operating lever. In this region, due to inevitable laminar leakage of the product—also caused by sliding of the piston during the tap working—there is always the presence of some product that is subjected to degradation thereby producing bacteria. In addition, due to sliding of the piston a bacteria-dragging action from such a region to the inside of the tank is produced. The solution proposed in the known art is obviously that of making seals between the tap and seat as much efficient as possible and again of reducing the stagnation region to the minimum. These solutions too appeared to be unsatisfactory.
On the other hand, the product difficulty in penetrating into the stagnation regions does not inhibit stagnation, but it only hinders the efficiency of the periodical sanitising operation on the apparatus. In fact, this operation is generally carried out by introducing an appropriate disinfectant solution into the tank. Since the residence time of the solution in the tank is much more limited than the residence time of the product, the more attempts are made to make the product leakage in the stagnation regions difficult, the more reaching of the stagnation regions themselves is unlikely to occur during the limited period of time for execution of the disinfecting operation.
It is a general aim of the present invention to obviate the above mentioned drawbacks by providing a machine of the mentioned type that however has a dispensing tap avoiding the above problems concerning bacteria production and pollution of the product.